[polls] SS 2.4 PollChoices DataObjectDecorator

I'm using SilverStripe 2.4 and the latest polls module to create and manage a simple multiple choice poll on my site. What I'm trying to do, is to extend the poll choices to have couple extra fields such as an image per choice. Pretty simple stuff, just can't figure out how to get the fields to show up in admin. Here's what I have so far: